Comparison of HbA1c and OGTT Criteria to Diagnose Diabetes Among Chinese

Impact of the 2020 China Diabetes Society Guideline on the Prevalence of Diabetes Mellitus and Eligibility for Antidiabetic Treatment in China

Purpose

This study aimed to estimate the impact of the 2020 China Diabetes Society's (CDS) guideline on the prevalence of diabetes mellitus and eligibility for antidiabetic treatment in China.

Material and Methods

Baseline data from the China Health and Retirement Longitudinal Study (CHARLS, 2011-2012) were used to estimate the prevalence of diabetes mellitus and compare the recommendations for antidiabetic medication and intensification of therapy between the 2017 and 2020 CDS guidelines.

Results

According to the 2017 CDS guideline, the prevalence of diabetes mellitus was 12.56% among Chinese adults who were ≥45 years of age. However, according to the 2020 CDS guideline, 0.65% (0.35%, 1.20%), or 3.54 (2.50, 4.57) million Chinese adults who were ≥45 years would additionally be diagnosed with diabetes mellitus. Among Chinese adults not taking antidiabetic medications, 1.06% (0.87%, 1.28%), or 5.37 (4.36, 6.38) million Chinese adults with diabetes mellitus were recommended to start antidiabetic medication according to the 2017 CDS guideline, while 1.27% (1.01%, 1.58%), or 6.44 (5.29, 7.60) million Chinese adults with diabetes would be recommended to initiate antidiabetic medication according to the 2020 CDS guideline. Among Chinese adults taking antidiabetic medication, 51.59% (44.19%, 58.93%), or 18.35 (15.58, 21.12) million Chinese adults with diabetes received antidiabetic treatment but had a hemoglobin A1c (HbA_1c) level higher than that mentioned in the 2017 and 2020 CDS guidelines.

Conclusion

The addition of HbA_1c in the 2020 CDS guideline will result in a modest increase in the number of Chinese adults who are diagnosed with diabetes and diabetes patients recommended for antidiabetic medication; however, the 2020 CDS guideline does not affect the number of diabetes patients eligible for intensification of treatment.

Sex and age discrepancy of HbA1c and fetal hemoglobin determined by HPLC in a large Chinese Han population

BACKGROUND

It is accepted that HbA1c is an effective indicator to evaluate glycemic control. Fetal hemoglobin (HbF) is seldom measured because traditional detection is inconvenient. In this regard, there may be an advantage in using HPLC autoanalysis of HbA1c as a surrogate method for HbF detection. The aim of the present study was to explore the distribution of HbA1c and HbF in a large Chinese Han population.

METHODS

In all, 70 553 blood samples were collected between January 2012 and June 2016. Study subjects were inpatients undergoing routine medical care and were divided into four groups based on age: Group A, 20-39 years; Group B, 40-59 years; Group C, 60-79 years; and Group D, ≥80 years. Blood HbA1c and HbF concentrations were measured by HPLC using a Tosho Bioscience (Tokyo, Japan) G8 analyzer.

RESULTS

There was a positive association between HbA1c and age, and a negative association between HbF and age. The concentration range of HbF was narrow and HbF concentrations were significantly higher in females than males, regardless of age (median 0.7% vs 0.6%, respectively; P < 0.0001). There was a low degree of correlation between HbF and HbA1c (r = 0.181, P < 0.0001). Although median HbA1c levels were higher in male than female subjects aged 20-59 years (5.5% vs 5.4%, respectively, in Group A; 5.9% vs 5.8%, respectively in Group B), in the 60-79 years group, HbA1c levels were lower in males than females (6.1% vs 6.2%, respectively; P < 0.0001).

CONCLUSIONS

The data suggest that sex and age should be considered in clinical interpretation of HbA1c.

Re-examining the sensitivity of HbA1c to screen for diabetes mellitus

BACKGROUND

One of the laboratory tests recommended by the American Diabetes Association (ADA) to screen for diabetes mellitus (DM) is HbA1c, and it is particularly suitable for segments of the population that cannot or are unwilling to fast for a screening test. The aim of this study was to determine whether HbA1c would be a useful tool to screen for DM in a real-world setting if ADA guidelines for repeat testing to confirm the diagnosis of DM are strictly adhered to.

METHODS

A retrospective database study was performed by extracting demographic and laboratory data from a chronic disease registry that collects data on adults from three tertiary hospitals and nine large primary care clinics in Singapore. Data were extracted and analyzed for adults not previously known to have DM whose data was captured in the registry between 2005 and 2016 with HbA1c and at least two diagnostic tests for DM (fasting plasma glucose or 2-h plasma glucose) performed within 4 weeks after HbA1c determination.

RESULTS

In all, 3928 adults were included in this study. The sensitivity, specificity, and area under the receiver operating characteristic curve for HbA1c at a threshold of 6.5% were 85.2%, 82.3%, and 0.914, respectively. A higher sensitivity was found in female adults, younger adults, and those of non-Chinese ethnicity.

CONCLUSIONS

The sensitivity of HbA1c as a screening test for DM in this study was significantly higher than that reported previously. This work provides additional evidence supporting the inclusion of HbA1c as one of the screening tests for DM.

Can HbA1c replace OGTT for the diagnosis of diabetes mellitus among Chinese patients with impaired fasting glucose?

BACKGROUND

HbA1c ≥ 6.5% has been recommended as a diagnostic criterion for the detection of diabetes mellitus (DM) since 2010 because of its convenience, stability and significant correlation with diabetic complications. Nevertheless, the accuracy of HbA1c compared to glucose-based diagnostic criteria varies among subjects of different ethnicity and risk profile.

OBJECTIVES

This study aimed to evaluate the accuracy of HbA1c for diagnosing DM compared to the diagnosis by oral glucose tolerance test (OGTT) and the optimal HbA1c level to diagnose DM in primary care Chinese patients with impaired fasting glucose (IFG).

METHODS

A cross-sectional study was carried out in three public primary care clinics in Hong Kong. About 1128 Chinese adults with IFG (i.e. FG level between 5.6 and 6.9 mmol/l in the past 18 months) were recruited to receive paired OGTT and HbA1c tests. Sensitivities and specificities of HbA1c at different threshold levels for predicting DM compared to the diagnosis by OGTT were evaluated. A receiver operating characteristic (ROC) curve was used to determine the optimal cut-off level.

RESULTS

Among the 1128 subjects (mean age 64.2±8.9 year, 48.8% male), 229 (20.3%) were diagnosed to have DM by OGTT. The sensitivity and specificity of HbA1c ≥6.5% were 33.2% and 93.5%, respectively, for predicting DM diagnosed by OGTT. The area under the ROC curve was 0.770, indicating HbA1c had fair discriminatory power. The optimal cut-off threshold of HbA1c was 6.3% for discriminating DM from non-DM, with sensitivity and specificity of 56.3% and 85.5%, respectively. HbA1c ≥ 5.6% has the highest sensitivity and negative predictive value of 96.1% and 94.5%, respectively.

CONCLUSIONS

HbA1c ≥ 6.5% is highly specific in identifying people with DM, but it may miss the majority (66.8%) of the DM cases. An HbA1c threshold of <5.6% is more appropriate to be used for the exclusion of DM. OGTT should be performed for the confirmation of DM among Chinese patients with IFG who have an HbA1c between 5.6% and 6.4%.

Evaluation of HbA1c criteria for diagnosis of diabetes mellitus: a retrospective study of 12 785 type 2 Saudi male patients

Recently, American Diabetic Association has recommended glycated hemoglobin (HbA1c ≥6.5%) as an alternate to fasting plasma glucose (FPG ≥7.0 mmol/L) for diagnosis of diabetes. However, studies from different groups showed inconsistent results with the use of HbA1c criteria. We examined the validity of HbA1c cut-point of 6.5% for diagnosis of diabetes. A total of 12 785 male diabetic patients (FGP ≥7.0 mmol/L), aged 56.27 ± 13.32 years were included. The average values of FPG and HbA1c of all the 12 785 patients were 10.127 ± 0.026 mmol/L and 8.729 ± 0.013%, respectively. Sub-grouping of patients into different age categories showed significantly high levels of FPG (10.934 ± 0.123 mmol/L) in the youngest group (age, ≥20-35 years) as compared to FPG (ranged from 10.021 ± 0.052 to 10.190 ± 0.050 mmol/L) in patients with other age categories. The level of HbA1c was highest in the youngest group (8.809 ± 0.056%) and lowest in the oldest group (8.653 ± 0.082%). There was a significant correlation between FPG and HbA1c (R = 0.571, p < 0.001). There were 484 patients below the diagnostic threshold (HbA1c <6.5%), resulting in 3.78% false negative predictions. Majority of the false negative patients were in the age group of 40-75 years and had borderline FPG (7.0-8.0 mmol/L) and HbA1c (6.0-6.5%). These findings suggest that Saudi individuals with HbA1c between 6.0% and 6.5% may be considered as "probable diabetic" and their status should be verified by combined FPG and HbA1c criteria.

The diagnostic threshold of HbA1c and impact of its use on diabetes prevalence-a population-based survey of 6898 Han participants from southern China

OBJECTIVE

The objective of this study is to determine the diagnostic threshold of HbA1c for diabetes and the impact of using it on diabetes prevalence.

METHODS

A population-based stratified study was conducted in 2010 among community-dwelling adults aged ≥35years in southern China. Participants without previously-diagnosed diabetes (PDD) took oral glucose tolerance test (OGTT) and HbA1c assay. HbA1c diagnostic threshold was determined by receiver operating characteristic curve.

RESULTS

A total of 6989 participants with mean age of 52years were recruited. The area under curve of HbA1c was 0.903 (95% CI: 0.883-0.922), with optimal cut-off value at 6.25% (sensitivity 75.6% and specificity 91.9%). There were 449 (6.42%) patients with PDD and 422 (6.04%), 815 (11.66%) and 918 (13.13%) new cases diagnosed by OGTT, HbA1c ≥6.25% or either, respectively. When either HbA1c or OGTT was used, newly-diagnosed diabetes prevalence increased by 117.4%.

CONCLUSIONS

Diabetes is prevalent in southern China. Near half of the patients go undetected with current diagnostic criteria. HbA1c ≥6.25% may be the diagnostic threshold value but needs further verification. The introduction of HbA1c threshold into diabetes diagnosis in China will cause a substantial increase in diabetes prevalence and great challenge on the public healthcare system.

Prevalence of diabetes in Malaysia and usefulness of HbA1c as a diagnostic criterion

AIM

The prevalence of diabetes mellitus among Malaysians aged ≥ 30 years of age has increased by more than twofold over a 20-year period. This study aimed to determine the current status and to evaluate the diagnostic usefulness of the HbA(1c) cut-off point of 48 mmol/mol (6.5%).

METHODS

Using a two-stage stratified sampling design, participants aged ≥ 18 years were recruited from five zones selected to represent Malaysia. An oral glucose tolerance test was performed on all those not known to have diabetes.

RESULTS

A total of 4341 subjects were recruited. By World Health Organization criteria, the prevalence of diabetes mellitus was 22.9%; of that percentage, 10.8% was known diabetes and 12.1% was newly diagnosed diabetes. Diabetes was most prevalent amongst Indians (37.9%) and Malays (23.8%). Prevalence of new diabetes mellitus was only 5.5% (95% CI 4.9-6.3) when based on the HbA(1c) diagnostic criteria of 48 mmol/mol (6.5%) and, although the cut-off point was highly specific (98.1%), it was less sensitive (36.7%) compared with 45 mmol/mol (6.3%), which showed the optimal sum of sensitivity (42.5%) and specificity (97.4%) in identifying new diabetes mellitus.

CONCLUSION

This study recorded an overall diabetes prevalence of 22.6%, almost a twofold increase from 11.6% reported in 2006. This was likely attributable to the higher prevalence of new diabetes (12.1%) diagnosed following an oral glucose tolerance test. An HbA(1c) of 45 mmol/mol (6.3%) was found to be a better predictive cut-off point for detecting new diabetes in our multi-ethnic population.

Diagnostic accuracy of HbA1c in diabetes between Eastern and Western

BACKGROUND

In 2010, the American Diabetes Association recommended the use of HbA1c as a diagnostic criterion for diabetes. However, HbA1c is not an accepted diagnostic tool for diabetes in Eastern Asia, because genetic differences compromise the standardization of the diagnostic cut-off point.

OBJECTIVES

This study evaluated differences in the use of HbA1c for diagnosing diabetes in Eastern and Western populations and investigated whether HbA1c cut-off point of ≥ 6.5% is diagnostic of diabetes in patients from Eastern Asia.

METHODS

Literature was obtained from MEDLINE, EMBASE and Cochrane databases. The pooled sensitivity and specificity of each HbA1c cut-off point were extracted and compared between Western and Eastern populations. Differences in the cut-off point for diagnosing diabetes in each region were compared by examining differences in the area under summary receiver operating characteristic (SROC) curves.

RESULTS

Twelve publications from Eastern countries (n = 59,735) and 13 from Western countries (n = 22,954) were included in the analysis. Areas under SROC curves in the Eastern and Western groups were 0.9331 and 0.9120, respectively (P = 0.98). The cut-off point of the highest Youden index was 6.0%. At the HbA1c cut-off point of 6.5%, the pooled sensitivity and specificity were 58.7% and 98.4% for Eastern countries and 65.5% and 98.1% for Western countries, respectively.

CONCLUSIONS

HbA1c exhibits the same diagnostic value for diabetes in Eastern and Western populations. In both populations, HbA1c levels > 6.0% identify the population at high risk of diabetes, and HbA1c > 6.5% is diagnostic of clinically established diabetes.

Screening South Asians for type 2 diabetes and prediabetes: (1) comparing oral glucose tolerance and haemoglobin A1c test results and (2) comparing the two sets of metabolic profiles of individuals diagnosed with these two tests

BACKGROUND

The glycated haemoglobin A1c (HbA1c) level may be used for screening for type 2 diabetes and prediabetes instead of a more burdensome oral glucose tolerance test (OGTT). However, among the high-risk South Asian population, little is known about the overlap of the methods or about the metabolic profiles of those disconcordantly diagnosed.

METHODS

We included 944 South Asians (18-60 years old), whom we screened with the HbA1c level and the OGTT in The Hague, the Netherlands. We calculated the area under the receiver-operator characteristic curve (AUROC) with a 95% confidence interval of HbA1c using the American Diabetes Association classifications, and determined the sensitivity and specificity with 95% confidence intervals at different thresholds. Moreover, we studied differences in metabolic characteristics between those identified by HbA1c and by the OGTT alone.

RESULTS

The overlap between HbA1c and OGTT classifications was partial, both for diabetes and prediabetes. The AUROC of HbA1c for OGTT defined diabetes was 0.86 (0.79-0.93). The sensitivity was 0.46 (0.29-0.63); the specificity 0.98 (0.98-0.99). For prediabetes, the AUROC was 0.73 (0.69-0.77). Each of the 31 individuals with diabetes and 353 with prediabetes identified with the HbA1c level had a high body mass index, large waist circumference, high blood pressure, and low insulin sensitivity, all of which were similar to the values shown by those among the 19 with diabetes or 62 with prediabetes who only met the OGTT criteria, but not the HbA1c criteria.

CONCLUSIONS

The HbA1c level identified a partially different group than the OGTT did. However, both those identified with the HbA1c level and those identified with the OGTT alone were at increased metabolic risk.

TRIAL REGISTRATION

Dutch Trial Register: NTR1499.

Change in visceral adiposity independently predicts a greater risk of developing type 2 diabetes over 10 years in Japanese Americans

OBJECTIVE

Visceral adiposity is an important risk factor for cardiovascular disease and type 2 diabetes. We sought to determine whether change in intraabdominal fat area (IAF) over time predicts subsequent development of diabetes.

RESEARCH DESIGN AND METHODS

We followed up 436 nondiabetic Japanese-American subjects (mean age 51.9 years, mean BMI 24.2 kg/m(2), 54% male) for development of diabetes. We fit a logistic regression model to examine the association over a 10-year follow-up between change in IAF at 5-year follow-up and other fat areas (measured by computed tomography) and development of incident diabetes, adjusted for age, sex, family history of diabetes in a first-degree relative, second-generation versus third-generation Japanese American (Nisei vs. Sansei), baseline IAF, BMI, weight change over time, smoking status, physical activity level, and subcutaneous fat (SCF) depot areas.

RESULTS

Cumulative incidence of diabetes was 20.4% at 10 years. Mean change in IAF was 10.9 cm(2). An increase of 1 SD in IAF was associated with a 1.65-fold increase in the odds of diabetes over 10 years (OR = 1.65, 95% CI 1.21-2.25) after adjusting for the above covariates. This association was also independent of changes in thoracic, thigh, and abdominal SCF, as well as change in weight.

CONCLUSIONS

We conclude that baseline IAF and accumulation of fat in this area over time are independent predictors of the development of type 2 diabetes in Japanese Americans.

Comprehensive identification of glycated peptides and their glycation motifs in plasma and erythrocytes of control and diabetic subjects

Nonenzymatic glycation of proteins sets the stage for formation of advanced glycation end-products and development of chronic complications of diabetes. In this report, we extended our previous methods on proteomics analysis of glycated proteins to comprehensively identify glycated proteins in control and diabetic human plasma and erythrocytes. Using immunodepletion, enrichment, and fractionation strategies, we identified 7749 unique glycated peptides, corresponding to 3742 unique glycated proteins. Semiquantitative comparisons showed that glycation levels of a number of proteins were significantly increased in diabetes and that erythrocyte proteins were more extensively glycated than plasma proteins. A glycation motif analysis revealed that some amino acids were favored more than others in the protein primary structures in the vicinity of the glycation sites in both sample types. The glycated peptides and corresponding proteins reported here provide a foundation for potential identification of novel markers for diabetes, hyperglycemia, and diabetic complications in future studies.